Circuit interrupter



Jan. 2z, 1929.

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D. ULREY El' AL CIRCUIT INTERRUPTER Filed July 5. 1926 2 sheets-sheet 2 ,H 3 2 w M w M n 5. Q a M MJ m 2. 2 2 .0 5 zu Q 4 2 v w 2 `a n b 2 ooo m M M w 2 r 2 2 2 4 c/u 2 4 4 4 l 4 n 4 wam w mim WM; w www .A 0 .M /L M pw YIVIVIIIIIIIIIIIII l/ Patented Jan. 22, 1929.

TES PAT ENI oFFl-CE.

.DA'YToN{IILREYJANDIESLIE NrcnIcHToN, or PITTSBURGH, rENNeYLvANIm'nsf s f@ sIefNolsns To-wnsTmGHoUsEvELEcTBIc AND muracrumecourm, -A oon- L f IORATION OFIPENNSYLVANIA.

- v CIRCUIT INTERBUPTEB..

j' ".urifnventioii relates tothermo-responsive circuit''interrupters and particularly. to interruptersv of ,the mercury-capillary-tube type? Aniobje'ct of oui` invention is toprovide "means forja circuit interrupt'er of the me1- (fury-'capiilary-tube type, whereby the heat generated in the mercury shall be confined substantially-to port-ion thereof where the current flowing therethrough is to be interupted. j L

'l 'Another objectA of `our vinvention is to pro-r vide a"circuit interrupte'ry ofl the mercurycapillaryftube'type, in which the' heat conducted to the terminals thereoi:` shall be compensated or'b'y resistor members in circuit therewith. i t

Another objecttolfour invention is to provide means'forprotecting the surface of a. circuit intferrupte'rv of the Vmercury-capillarytube type, at thepoint at which the circuit is broken. t

Another; objectof our invention is to provide means-for regulating the temperature at which a thermo-responsive circuit interrupter v ofthe mercury-capillary-tube type shall be Operable.

In practicing our invention, we provide a capillaryftube which has enlarged end portions and an intermediate elongated portion of relatively reducedsection, in which a body of current-conducting material, such as mercury, is contained. Terminal members are provided therefor, that extend into the current-conducting fluid, and are suitably sealed to the tube. We provide, also, the intermediatexportion ofjfthe capillary tube with a restrictedportion, whereby the mercury column contained therein shall be vaporized and brokensubstantially at` thisv portion. We d provide, also, means for 4compensating the heat conducted fromthe mercury to the terminals by providing resistor members in close proximity thereto and in. circuit therewith.

In order'to `confine the heat generated in the current-conducting iiuid contained within the capillary tube to aid in the vaporization of the fluid, we providethermal insulating means which comprises `an evacuated envelopef disposed around the capillary tube.

L In the accompanying drawings,

Fig. 1 is a'view, in vertical section, of a deviceembodying our invention;

Fig. 2 is a view, in vertical section, of a modification. of the Fig.1; -Y .i I, Fig. 3 is a view, in vertical section, of a modified form of thecapillary tubev'empldyed in the devices `illustratedin Figs. 1 an 2; f

Fig. 4 isa View, in .verticalsectiom of another modivcation of the, device embodying our invention; I Fig. 5 is a view, in vertical section, .of another modification of the-device illustrated inA Figs. 1 and 2; and v Fig. 6 is a view, in vertical section, of a modification of the deviceslillustrated in Figs.1and2.

lReferring more particularly to. Fig. 1, a circuit interrupter 11 comprises a capillary tube 12 and an evacuated envelope 13. The capillary tube 12 is disposed within the envelope 13 and may be suspended thereinb-y resistor members 14 which are secured to terminal members 15 ofthe tube 12. The tube deyiee -I illustrated 12 is provided with enlarged end portions -16 and 17 and an intermediate elongated portion 18 of reduced section.y y

The elongated portion 18 is provided witha restricted portion 19 which extends towards the center thereof. A column 21 ofcurrentconducting fluid, such as mercury, is disposed within the tube 12. The terminal members 15 extend into the enlarged portions 16 and 17,

of the tube 12 andare so sealed therein as to be in circuit with the mercury column-21. The resistor members 14 are provided with terminals 2 2 which extend through the ends of the envelope 13 and are sealed therein.

Thev envelope 13 and the capillary tube 12 may be made of any suitable refractory ma*l terial such as quartz or glass, havingv a low extends into the other end. The closure mem-y ber 25 is` provided with a passageway 26 and a needle valve 27 for adjusting the area of the opening 26. The tube 12 is supported within the envelope 23 :fromy the upper resistor 14 that is connected to the terminal 15. One of the resistor members 14 is so embedded In Fig. 3 of the drawings, we have illus-l trated a modified form of the capillary tube shown in Figs. 1 and 2. In this particular embodiment of the mercury tube 12, the portion 18 is lined with a refractory member 29, such as porcelain, and should preferably have substantially the same coefficient of expansion as the material of the tube 12. The porcelain tubular member 29 is fused with the portion 18 and is provided with a restricted portion 31.

In. Fig. 4 of the drawings, we have illustrated a. modification of the circuit inter'- rupter embodying our invention, which may be used for controlling a polyphase circuit. The relay 11. in this modification, comprises an evacuated envelope 32 which is provided with individual compartments 33 and 34 and a passageway 35. The effective opening of the passageway 35 is regulated by an adjusting means or needle valve 36. The capillary tubes 12 are disposed Within the compartments 33 and 34 and are supported from the ends of the envelope 32 by the resistor members 14. v

In Fig. 5 of the. drawings, a. modified form of the capillary tube 12 is illustrated and comprises a return-bent tube having an enlarged portion 37 and. two elongated .por-` tions 38 and 39 of relatively small section. The portions 38 and 39 are provided with restricted portions 41 and 42. vThe tube 12 is filled to asuitable level with a conducting fluid, such as mercury, after which the tube 12 is evacuated to a suitable degree. In some applications of our invention, it may be desirable to fill the tube 12 with an inert gas.

Terminal members 15 extend into the portions 38 and 39 and are sealed therewith. The tube 12 is dis osed within an` evacuatedenvelope 43.wh1ch may be sealed to the portions 38 and 39 of the tube 12. The terminal members 15 are provided with resistor members 14 to compensate for heat which may be conducted'from the mercury within the portions 38 and 39 to the terminal members 15.

In Fig. 6zof the drawings, the capillary tube 12 has only the elongated portion 18 'thereof surrounded by an evacuated envelope 44 which is preferably sealed to the member 18. f

The operation ofthe device illustrated in Figs. 1 to 6, inclusive, isV based upon the capillary action of the portions 18 of the capillary vtubes illustrated in Figs. 1 to' 4, inclusive, and Fig. 6, As current passes through the column ofv mercury from the terminal members 22, the mercury column is caused to increase in temperature as a result of the IR loss which occurs therein. Asthe mercury is heated, the column expands and, since an evacuated envelope encloses the tube 12, the heat generated therein is confined thereto and causes the mercurynto expand.- As the mercury increases in temperature, it finally vaporizes and becomes discontinuous .at substantially the restricted portions 19 of the elongated portion 18 of the tubes, as illustrated.' p

The discontinuity of the mercury at the rcstricted portions 19'therefore, causes the current fiowing therethrough to be interrupted. By providing a sealed envelope for enclosing the tubes 12, a thermal insulation is provided whereby the portion 18 of the tube 12 may be made larger in section, so as to have larger current carrying capacity, in order that the device illustrated inthe drawings may have more practical value as a circuit interrupting device.

The thermal insulating properties of the envelopes 13, 23, 32, 43 and 44, illustrated in Figs. 1, 2, and 4 to 6, inclusive, may be greatly improved by providing a highly reflecting surface 45, preferably on the inside surfaces thereof. The surface 45 may be obtained by plating with silver or other suitable material. The surface 45 acts as a reflector for the heat rays emitted from the heated mercury 19 and reflects them back again to the mer` eury. The capillary tubes 12 may be provided with .a reiiecting surface if desired, although such construction need not, necessarily, e adhered to.

, In Fig. 6 of the drawings, the envelope 44 encloses the portion 18 only of the capillary tube 12. this particular modification, the heat generatedin the portion 18 of the tube 12 is confined thereto and aids in vaporizing the mercury at substantially the restricted tion of the devices illustrated in the other figures, except that the interruption of the circuit may be accomplished lat two points located substantially at the restricted portions 41 and 42 of the portions 38 and39. Ihe vaporization of the mercury columns 19 will take place near the top of the tube 12, as illustrated, because the head of mercury thereabove is not very great, and the pressure tending to retard the disrupting of the mercury column does not have much effect.

The needle valves 27 and 36, illustrated in Figs. 2 and 4, respectively, are provided to control the temperature of the capillary tubes 12 in accordance with a predetermined value of current that is to be permitted to pass through an electric translating device, in circuit with the relay 1l. It a large current is to be passed through the electric translating device,vthe needle valve Iis turned outwardly and thai full effective o ning. With the full effec-` tive opening, a arger current will be required to increase the temperature of the mercury to the vaporization point to cause the circuit to be broken.

If the needle valves are turned inwardly to reduce the effective opening of vthe passages 26 and 35, a smaller current will be re uired to cause vaporization ofthe mercury co umn, with consequent interruption of the current flowing therethrough.

By our invention. we have provided a circuit interrupter of the mercury-capillarytube type in which the heat generated in the mercury column is confined at substantially the points where vaporization thereof occurs for mterru ting the circuit. We have also provided a justing means whereby currents of different values may be interrupted with a 'ven device.

iile we have illustrated various modifications of the device embodying our invention, other changes may be made therein without de arting from the spirit and scope thereof. e desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and the appended claims.

We claim as our invention:

l. In a thermally-actuable circuit interrupter, the combination with an evacuated, refractory electrically non-conducting member; said member having enlarged end portions and a relatively narrow, elongated intermediate portion, said member having electrically-conducting :duid therein, and terminal members extending into said fluid at opposite ends of said intermediate portion, of means for thermally insulating said evacuated refractory member comprising an evacuated and reflecting envelope disposed therearound.

2. In a thermally-actuable circuit interrupter, the combination with an evacuated, 1e ractory electrically non-conducting member, said member having enlarged end portions and a relatively narrow, elongated intermediate portion, said member having electrically-conducting fluid therein and terminal members extending into said fluid at opposite ends of said intermediate portion, of means for thermally insulating the intermediate portion of said evacuated refractory member comprising an evacuated envelope disposed therearound.

3. In a thermally-actuable circuit interrupter, the combination with a refractory electrically non-conducting member, sa1d member having enlarged end portions and a relatively narrow, elongated intermediate portion, said member having electricallyconducting fluid therein, and terminal members extending into said fluid at opposite ends of said intermediate portion, of means for regulating the temperature of said refractory member in accor ance with a predetermined value of electric current passing through said fluid, said means comprising a Aheat insulating envelope disposed therearound and means for controlling the flow of a cooling medium between inner walls of said envelope.

4. In a thermally-actuable circuit interrupter, thecombination with a refractory, electrically non-conducting member, said member having enlarged end portions and a relatively narrow, elongated intermediate portion, said member having electrically-conducting fluid therein and terminal members extending into said fluid at opposite ends of said intermediate portion, of means for maintaining the operating temperature of said refractory member at a predetermined value in accordance with a predetermined value of current passing therethrough, comprising a heat insulating envelope disposed around the intermediate portion thereof and resistor members in circuit with said terminal members for compensating for heat flow from said 1ntermediate portion to said terminal memers.

5. In a thermally-actuable circuit interrupter, the combination with a sealed, electrically-insulating container, electricallyconducting fluid disposed therein, said container having enlarged end portions and an elongated intermediate portion of reduced section, and terminal members in circuit with said fluid, of means for regulating the temperature of said container comprising an evacuated envelope disposed therearound and means for permitting a cooling medium to flow between inner walls of said envelope.

6. In a thermally-actuable circuit interrupter, the combination with a. plurality of sealed, electrically-insulating containers having current-conducting fluid therein, and terminal members in circuit with the fluid of said containers, of means for regulating the temperature of said containers comprising an envelope disposed therearound.

7. In a thermally-actuable circuit interrupter. the combination with a plurality of sealed, electrically-insulat-ing containers having current-conducting fluid therein, said containers having enlarged end portions and elongated intermediate portions of reduced section. and terminal members in circuit with the fluid of said containers, of means thermally insulating said containers comprising a plurality of integral evacuated envelopes enclosing said containers individually.

8. In a thermally-actuable circuit interrupter, the combination with a plurality of sealed, electrically-insulating containers having current-conducting fluid therein, said containers having enlarged end portions and elongated intermediate portions of reduced section, and terminal members in circuit with 'roo the fluid of said containers, of means for controlling the temperature of said containers comprising` an evacuated envelope disposed vtherearouml and means for regulating;r the How of a coolingir medium therebetween.

2).' thermally-responsive circuit interrupter comprising' a sealed electrically` in- Asulating' capillary tube, said tube havin: rurrent-eonducting Huid therein and terminal members at the ends thereof in circuit there.- with. and means for thermally insulat ing said tube comprisingg an evacuated envelopil dispo.` ed therearound.

10. A thermally-responsive circuit interrupter comprising a sealed electrically insulating capillary tubel` said tube having current-conducting tluid therein and terminal members at the ends thereof in circuit therewith, and means for thermally insulating;r said tube comprising an evacuated 'and refleeting. envelope disposed therearound.

11. A thermo-responsive circuit interrupter comprising a sealed electrically insulating capillary tube, said tube having current-conducting fluid therein, and means for thermally insulating said tube comprising an evacuated envelope disposed therearound and integral therewith.

12. A thermally-responsive circuit interrupter comprising' a sealed electrically insulating capillary tube. said tube havingf current-conducting fluid therein and terminal members at the. ends thereof in circuit therewith. and means for regulating the temperature of said tube comprising an evacuated envelope disposed therearound` resistor members in circuit with said terminal members and means for controlling.,r the flow of a, cooline' medium between inner walls of the envelope'.

In testimony whereof. We have hereunto subscribed our names this 24th day of June, 1926.

DAYTON ULREY. LESLIE N. CRICHTON. 

